Children and parents frequently report a variety of symptoms following mild closed-head injuries (CHI). These post-concussive symptoms often occur in the absence of any objective evidence of brain trauma and despite substantial recovery on standardized cognitive testing. Debate therefore continues regarding the determinants and consequences of post-concussive symptoms following mild CHI. The specific aims of the proposed study are to examine the (1) natural history, (2) prediction, and (3) consequences of post-concussive symptoms in children with mild CHI. The study will involve 200 8 to 15 year old children with mild CHI and 100 with mild orthopedic injuries not involving the head in a concurrent cohort/prospective research design. The children and their families will be assessed four times during the first year post-injury (i.e., at 1 week, 1 month, 3 months, and 12 months post-injury). Post-concussive symptoms will be assessed using rating scales and interviews, with both children and parents as informants. Predictors of post-concussive symptoms will include injury characteristics, cognitive abilities, and non-injury related child and family variables. Outcomes to be assessed include school performance, health utilization, and other aspects of child and family functioning. The study will examine three major hypotheses: (1) Children with mild CHI will display more post-concussive symptoms than children with mild orthopedic injuries, although group differences in incidence are expected to vary as a function of symptom type and time since injury; (2) The incidence of post-concussive symptoms will be related to (a) injury characteristics, (b) the extent to which the injury results in impairment in cognitive performance, and (c) non-injury related child and family factors. These relationships again are expected to vary as a function of symptom type and time since injury; and (3) Severe post-concussive symptoms will be associated with more child disability. The study will result in a clearer understanding of the roles that injury characteristics, post-injury cognitive status, and non-injury related factors play in the onset and persistence of post-concussive symptoms following mild CHI in children and adolescents. The study also will provide insights into the functional consequences of those symptoms for children. The findings will help resolve the scientific controversy regarding the outcomes associated with mild CHI, and will assist physicians and other health care providers in identifying the sequelae of mild CHI and managing them effectively.